Currently available procedures for treating cancer have several drawbacks: (1) existing chemotherapeutic agents are not as effective as required against late stage/metastatic cancers, (2) many chemotherapeutic regimens have significant side effects, and (3) even after a course of chemotherapy, there is a significant possibility that the cancerous growth will re-occur. Accurate methods for identifying and targeting cancer stem cells not only permit improved medical diagnosis and treatment of the associated cancer, but also enable drug screening for developing or identifying drugs effective against cancer regenerating cells such as cancer stem cells.
Evidence is accumulating that primitive cancerous stem cells for hematopoietic cancers and several types of solid tumors exist. See e.g., Cooper, G. M. ELEMENTS OF HUMAN CANCER, Jones and Bartlett Publishers, 1992, ISBN: 0867201916; Bonnet D. and Dick J. E. Human acute myeloid leukemia is organized as a hierarchy that originates from a primitive hematopoietic cell, Nature Medicine 3: 730-737 (1997); Park C. H., Bergsagel D. E., and McCulloch E. A. Mouse myeloma tumor stem cells: a primary cell culture assay, J. Nat. Cancer Inst. 46: 411-422 (1971); Hamburger A. W. and Salmon S. E. Primary bioassay of human tumor stem cells, Science, 197: pp. 461-463 (1977); and U.S. Pat. No. 4,411,990 to Salmon, et al. entitled Primary bioassay of human tumor stem cells, issued Oct. 25, 1983.
Current methods for diagnosing or treating cancer, removing cancer cells from transplant grafts prior to injection into a patient, or methods to screen the efficacy of anti-cancer agents in completely eliminating cancer cells, do not account for the presence of cancer stem cells, which can propagate, differentiate into mature cancer cells and self-renew, thereby reforming cancers and leading to remissions.
Accordingly, there exists a need for new methods for diagnosing or treating cancer, removing cancer cells from transplant grafts prior to injection into a patient, and methods to screen the efficacy of anti-cancer agents in eliminating cancer cells, which account for and/or are specifically directed to cancer stem cells and/or progenitor cells.